1. Field of the Invention
This invention relates to an air conditioner with a sub-condenser which can be used for air conditioning without reversing the flow of refrigerant during the refrigerating cycle, particularly for a car or electric car.
2. Discussion of the Related Art
In a conventional air conditioner for a car, a refrigerating cycle is used for cooling and heated engine water is used for heating. But for an electric car, there is no engine defining a powerful heat generating source for heating purposes, so it is necessary to heat using the refrigerating cycle. A heat pump is known using a heat exchanger which is used as an evaporator during cooling by reversing refrigerant flow, but this heat pump is not suitable for a car use because a four-way valve has to be rotated in order to switch between the flow paths. There is known an air conditioner having a sub-condenser installed at the position near the passenger compartment of a car, and being equipped with an evaporator in addition to a main condenser installed at the position not connected to the passenger compartment A bypass flow path is provided for refrigerant not passing the main condenser, as well as a refrigerant returning flow path to return refrigerant from the main condenser to the area between the evaporator and a compressor. By applying these structures, refrigerant can flow into only the sub-condenser but not into the main condenser, and refrigerant accumulated at the main condenser can flow using the compressor through the refrigerant returning flow path, which results in car passenger compartment heating available at the sub-condenser. However, the structures mentioned require a total of four T-shaped connections because both ends of the bypass flow path and both ends of the refrigerant returning flow path have to be connected to the refrigerant main flow piping. This connecting principle is disadvantageous because the piping structure is difficult to arrange, cannot be arranged neatly, and needs troublesome piping works and costly pipings and piping accessories.